/// <summary>
/// Creates a new module script provider that loads modules against a set of
/// privileged and fallback URIs.
/// </summary>
/// <remarks>
/// Creates a new module script provider that loads modules against a set of
/// privileged and fallback URIs. It will use the specified heuristic cache
/// expiry calculator and security domain provider.
/// </remarks>
/// <param name="privilegedUris">
/// an iterable providing the privileged URIs. Can be
/// null if no privileged URIs are used.
/// </param>
/// <param name="fallbackUris">
/// an iterable providing the fallback URIs. Can be
/// null if no fallback URIs are used.
/// </param>
/// <param name="urlConnectionExpiryCalculator">
/// the calculator object for heuristic
/// calculation of the resource expiry, used when no expiry is provided by
/// the server of the resource. Can be null, in which case the maximum age
/// of cached entries without validation will be zero.
/// </param>
/// <param name="urlConnectionSecurityDomainProvider">
/// object that provides security
/// domain objects for the loaded sources. Can be null, in which case the
/// loaded sources will have no security domain associated with them.
/// </param>
public UrlModuleSourceProvider(IEnumerable<Uri> privilegedUris, IEnumerable<Uri> fallbackUris, UrlConnectionExpiryCalculator urlConnectionExpiryCalculator, UrlConnectionSecurityDomainProvider urlConnectionSecurityDomainProvider)
{
this.privilegedUris = privilegedUris;
this.fallbackUris = fallbackUris;
this.urlConnectionExpiryCalculator = urlConnectionExpiryCalculator;
this.urlConnectionSecurityDomainProvider = urlConnectionSecurityDomainProvider;
}
/// <exception cref="System.IO.IOException"></exception>
internal virtual bool UpdateValidator(URLConnection urlConnection, long request_time, UrlConnectionExpiryCalculator urlConnectionExpiryCalculator)
{
bool isResourceChanged = IsResourceChanged(urlConnection);
if (!isResourceChanged)
{
expiry = CalculateExpiry(urlConnection, request_time, urlConnectionExpiryCalculator);
}
return isResourceChanged;
}
private long CalculateExpiry(URLConnection urlConnection, long request_time, UrlConnectionExpiryCalculator urlConnectionExpiryCalculator)
{
if ("no-cache".Equals(urlConnection.GetHeaderField("Pragma")))
{
return 0L;
}
string cacheControl = urlConnection.GetHeaderField("Cache-Control");
if (cacheControl != null)
{
if (cacheControl.IndexOf("no-cache") != -1)
{
return 0L;
}
int max_age = GetMaxAge(cacheControl);
if (-1 != max_age)
{
long response_time = Runtime.CurrentTimeMillis();
long apparent_age = Math.Max(0, response_time - urlConnection.GetDate());
long corrected_received_age = Math.Max(apparent_age, urlConnection.GetHeaderFieldInt("Age", 0) * 1000L);
long response_delay = response_time - request_time;
long corrected_initial_age = corrected_received_age + response_delay;
long creation_time = response_time - corrected_initial_age;
return max_age * 1000L + creation_time;
}
}
long explicitExpiry = urlConnection.GetHeaderFieldDate("Expires", -1L);
if (explicitExpiry != -1L)
{
return explicitExpiry;
}
return urlConnectionExpiryCalculator == null ? 0L : urlConnectionExpiryCalculator.CalculateExpiry(urlConnection);
}
public URLValidator(Uri uri, URLConnection urlConnection, long request_time, UrlConnectionExpiryCalculator urlConnectionExpiryCalculator)
{
this.uri = uri;
this.lastModified = urlConnection.GetLastModified();
this.entityTags = GetEntityTags(urlConnection);
expiry = CalculateExpiry(urlConnection, request_time, urlConnectionExpiryCalculator);
}
